Medium-viscosity nitrocelluloses

The medium-viscosity nitrocelluloses have the broadest application range, a major field being furniture lacquers. They are also employed in paper and metal coatings as well as in reaction lacquers (e.g., acid-catalyzed lacquers and polyurethane paints). 

High-viscosity, medium-viscosity, and low-viscosity formulations of each type are available [2.3]. Important producers of nitrocellulose used in lacquers include Hercules (USA), ICI (UK), BNC (France), Wolff Walsrode (FRG), and NQB (Brazil). 

A second important criterion for classification of nitrocellulose is its average MW, which is more conveniently expressed as the viscosity of its solutions. Based on this, it is classified as low viscosity, medium viscosity, and high viscosity grades. 

A particularly marked change in the viscosity of nitrocellulose results from keeping it boiling in solutions of different reagents — bases and acids. In order to lower the viscosity of nitrocellulose, careful boiling in an alkaline medium is sometimes applied in practice. 

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